Oral Medicine & Radiology OROFACIAL PAIN-1 DEFINITION According to International association for the study of pain (IASP) pain is defined as :- “An unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.” Dr.S.Karthiga Kannan Porfessor Oral Medicine & Radiology

SPECIFIC LEARNING OBJECTIVES To know the pathophysiology of orofacial pain To know the classification of orofacial pain To know the clinical characteristics and treatment of Trigeminal Neuralgia (TN) Glossopharyngeal Neuralgia (GN) Post Herpetic Neuralgia (PHN)

PAIN PATHWAYS

CLASSIFICATION OF OROFACIAL PAIN CHORNIC OROFACIAL PAIN LOCAL DISEASES ☞Musculoskeletal diseases Temporomandibular disorder(TMD) Myofacial pain dysfunction syndrome (MPDS) Eagle’s syndrome ☞ Vascular diseases Migraine Cluster headach Temporal or Giant cell arteritis ☞ Neurologic disorders Trigeminal neuralgia Glossopharyngeal neuralgia Post herpetic neuralgia ☞ Psychogenic Pain Atypical facial pain Burning mouth syndrome Atypical odontalgia ☞ Dental causes Pulpal Pulpitis Dentin hypersensitivity Cracked tooth syndrome Apical periodontitis Periapical Abcess Gingivitis/Periodontitis ANUG Pericoronitis /pericoronal abcess Oral ulcers Oral Cancers ☞ ENT diseases like sinusitis, otitis media Pharygitis, ☞ Eye diseases – Conjunctivitis

Episodic pain ☛ Trigeminal neuralgia ☛ Glossopharyngeal neuralgia ☛ Post-herpetic neuralgia ☛ Giant cell arteritis Constant pain ☛ Burning mouth syndrome ☛ Atypical facial pain ☛ Atypical odontalgia ☛ Temporomandibular joint dysfunction Pattern of pain Loss of function or sensation ☛ Facial nerve palsy ☛ Trigeminal nerve paresthesia

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TRIGEMINAL NEURALGIA (TN) Synonym – ☛ Tic douloureux, ☛ Fothergill’s neuralgia Types ☛ Classical TN (85%) – caused by compression of sensory root by vascular anurysm. ☛ Secondary TN – caused by tumors, viralinfection, trauma, and multiple sclerosis. ☛ Is the most common of the cranial neuralgias ☛ Age predilection - older than 50 years of age.

CLINICAL FEATURES ☛ NATURE – Unilateral, Paroxysmal (occurs in episodes) awakes from sleep. ☛ QUALITY – Sharp, stabbing,electric shock like, piercing. ☛ INTESITY – Severe ☛ AGGRAVATING FACTORS – shaving, eating, washing face, speaking, exposure to wind. ☛ DURATION – from seconds to 2 minutes. ☛ SITE – Maillary, mandibular, Opthalmic dermatome in decending order, usually right side.

Clinical features ☛ TRIGGER ZONE - Pain in TN is precipitated by a light touch on a “trigger zone”(Allodynia) present on the skin or mucosa within the distribution of the involved nerve branch. ☛ Common sites for trigger zones include the nasolabial fold and the corner of the lip. ☛ REFRACTORY PERIOD - Just after an attack, touching the trigger zone will not precipitate pain. ☛ PAIN BEHAVIOR – spasm of ipsilateral facial muscles, Patient protects / cover that area.

DIFFERENTIAL DIAGNOSIS INVESTIGATIONS ☛ Cracked tooth Syndrome ☛ TN pain will be triggered by touching the soft tissue around the trigger zone, whereas pressure on the tooth is required to cause pain from a cracked tooth. ☛Local anesthetic blocks, which temporarily eliminate the trigger zone, may also be helpful in diagnosis. ☛ CT scan,MRI of the brain is indicated to rule out tumors, multiple sclerosis. ☛ Magnetic resonance tomographic angiography (MRTA) for vascular lesions.

MANAGEMENT OF TN MEDICAL SURGICAL ☛ Carbamazepine – 100 -200 mg / twice a day can be increased slowly ☛ Baclofen – 5-10mg thrice a day ☛ Oxcarbamazepine – 300mg/ thrice a day ☛ Gabapentin – 200-300mg/twice a day ☛ Phenytoin – 300 -600mg /day ☛ Lamotrigine 25mg/1-2 time perday ☛ Pheripheral Neurectomy ☛ Percutaneous Trigeminal Rhizotomy – TN ganglion level -Glycerol injection -Ballon compression -Radiofrequency rhizolysis ☛ Microvascular decompression (MVD) – Brainstem level ☛ Gamma knife stereotactic radiosurgery (GKS) – 70-90 Gy radiation.

GLOSSOPHARYNGEAL NEURALGIA (GN) ☛ ETIOLOGY – compression of nerve root by blood vessel or anurysm. ☛ TYPES ☛Pharyngeal GN Pharynx, posterior tongue are involved and radiate to ear, eyes, nose, maxilla, shoulder and even tip of tongue. ☛Tymphanic GN Ear pain radiating to pharynx ☛ NATURE OF PAIN -Paroxysmal, unilateral, moderate to severe pain ☛ QUALITY – Sharp, stabbing, shooting or lancinating. ☛ DURATION – Fraction of second to 2 minutes ☛ FREQUENCY – 5-12 every hour and may occur in cluster lasting for weeks to months.

☛ TRIGGER POINTS - Tonsillar region, posterior pharynx ☛ TRIGGER POINTS - Tonsillar region, posterior pharynx. ☛ AGGRAVATING FACTORS – swallowing, chewing, talking, coughing and yawning, sneezing and rubbing ear. ☛ COMPLICATIONS – GN may induce uncontrollable coughing, seizures, and cardiac arrythmias, bradycardia and syncope. ☛ TREATMENT ♐MEDICAL - Carbamazepin, baclofen, oxcarbazepin, gabapentin, lamotrigine and phenytoin. ♐SURGICAL – Microvacular decompression and Gamma knife stereotactic radiosurgery

POST HERPETIC NEURALGIA (PHN) ☛ PHN- Pain of herpes zoster that persists three or more months. ☛ AGE – common in > 50 yrs ☛ SITE - 22% - Opthalmic nerve is commonly affected. ☛NATURE OF PAIN - Burning constant pain & superimposed flashes of pain ☛QUALITY – burning, sharp, shooting, throbbing , stabbing. ☛AGGRAVATING FACTOR – Hypo pigmented scar acts as trigger points – Allodynia. ☛ COMPLICATION - Paresthesia- loss of sensation

MANAGEMENT ☛ Prevention by use of varicella zoster vaccine ☛ For those with active Herpes Zoster use of antiviral drugs early in the course of the disease ☛ Acyclovir: 800 mg 5 times / day for 2 Weeks. ☛ Famcyclovir 250 mg 3 times a day ☛ Systemic Corticosteroid Prednisolone - 60 mg / day for 1st week 30mg / day for 2nd week and 15mg / day for 3rd week Treatment should be started within 10days and continued for three weeks For those who develop PHN ☛ Topical therapy such as lidocaine. ☛ Topical application of Capsaicin , a selective c-fiber neurotoxin that deplete the substance P ☛ Tricyclic antidepressant therapy Amitriptyline 25-100 mg daily divided doses. ☛ Gabapentin 200-300 mg twice daily ☛ TENS - Trans Cutaneous Electrical Nerve Stimulation ☛ Opioids, Tramadol

Glossopharyngeal neuralgia Postherpetic neuralgia CLINICAL CHARARECTERISTICS Trigeminal neuralgia Glossopharyngeal neuralgia Postherpetic neuralgia 1.Site Face Throat, tonsillar region Forehead,eyes –opthalmic dermatome 2.Nature Sharp, stabbing, shooting Burning constant pain & superimposed flashes of pain 3.Severity Worst pain experienced Moderate to Severe 4.Initiating factors Light touch, washing Swallowing, chewing Allodynia – light touch 5.Relieving factors None

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